.bash_profile: Support hostname aliases defined in `~/.ssh/config`

`~/.ssh/config` allows for the usage of hostname aliases, formatted as follows:

    Host first_alias second_alias third_alias
    HostName foo.example.com

This change makes sure these aliases are parsed out individually and added to the autocomplete list.

Ref. #178.
.osx: Disable Notification Center

This also removes the annoying menu bar icon.

Ref. #168.
Use newlines at EOF consistently
.osx: Enable the MacBook Air SuperDrive on any Mac

Ref. #146.
.osx: Disable Dashboard

Ref. #136.
.osx: Configure spring loading for directories

Ref. #133.
.osx: Set highlight color to orange
.osx: Set sidebar icon size to medium
.osx: Fix typo
.brew: Install Lua 5.2

I need this specific version to test the new `GotoStatement`s in Lua during http://mths.be/luamin development.
.gitconfig: Remove the destructive `undopush` alias
Merge branch 'master' of https://github.com/mathiasbynens/dotfiles into upstream

* 'master' of https://github.com/mathiasbynens/dotfiles:
  .gitconfig: Remove the destructive `undopush` alias
  .brew: Install Lua 5.2
  .osx: Fix typo
  .osx: Set sidebar icon size to medium
  .osx: Set highlight color to orange
  .osx: Configure spring loading for directories
  .osx: Disable Dashboard
  .osx: Enable the MacBook Air SuperDrive on any Mac
  Use newlines at EOF consistently
  .osx: Disable Notification Center
  .bash_profile: Support hostname aliases defined in `~/.ssh/config`

Conflicts:
	.bash_profile
	.bash_prompt
Merge branch 'upstream'

* upstream:
  .gitconfig: Remove the destructive `undopush` alias
  .brew: Install Lua 5.2
  .osx: Fix typo
  .osx: Set sidebar icon size to medium
  .osx: Set highlight color to orange
  .osx: Configure spring loading for directories
  .osx: Disable Dashboard
  .osx: Enable the MacBook Air SuperDrive on any Mac
  Use newlines at EOF consistently
  .osx: Disable Notification Center
  .bash_profile: Support hostname aliases defined in `~/.ssh/config`
move Homebrew BASH completion to .extra